ALPK1 missense pathogenic variant in five families leads to ROSAH syndrome, an ocular multisystem autosomal dominant disorder.

PURPOSE: To identify the molecular cause in five unrelated families with a distinct autosomal dominant ocular systemic disorder we called ROSAH syndrome due to clinical features of retinal dystrophy, optic nerve edema, splenomegaly, anhidrosis, and migraine headache. METHODS: Independent discovery exome and genome sequencing in families 1, 2, and 3, and confirmation in families 4 and 5. Expression of wild-type messenger RNA and protein in human and mouse tissues and cell lines. Ciliary assays in fibroblasts from affected and unaffected family members. RESULTS: We found the heterozygous missense variant in the ɑ-kinase gene, ALPK1, (c.710C>T, [p.Thr237Met]), segregated with disease in all five families. All patients shared the ROSAH phenotype with additional low-grade ocular inflammation, pancytopenia, recurrent infections, and mild renal impairment in some. ALPK1 was notably expressed in retina, retinal pigment epithelium, and optic nerve, with immunofluorescence indicating localization to the basal body of the connecting cilium of the photoreceptors, and presence in the sweat glands. Immunocytofluorescence revealed expression at the centrioles and spindle poles during metaphase, and at the base of the primary cilium. Affected family member fibroblasts demonstrated defective ciliogenesis. CONCLUSION: Heterozygosity for ALPK1, p.Thr237Met leads to ROSAH syndrome, an autosomal dominant ocular systemic disorder.

Prevalence and correlates of bleeding and emotional harms in a national US sample of patients with venous thromboembolism: A cross-sectional structural equation model.

INTRODUCTION: Venous thromboembolism (VTE) including deep vein thrombosis (DVT) or pulmonary embolism (PE) is associated with reduced survival, poorer quality of life, and substantial health-care-costs. Limited research, primarily qualitative, suggests that those with VTE may have elevated fear of recurrence, and associated emotional dysfunction and distress. METHODS: A national online survey was administered to 907 patients who had experienced a VTE event in the past two years. The survey assessed for the prevalence of self-reported bleeding harms associated with VTE, the levels of anxiety, depression, cognitive dysfunction and distress experienced by patients, and a range of potential psychosocial correlates that may be associated with these bleeding or emotional harms. RESULTS: The majority (63.0%) of respondents had experienced at least one bleeding related harm following their VTE diagnosis, and 40.6% indicated they experienced fear of another clot often or almost all the time. One-in-four (24.7%) and one-in-ten (11.6%) had abnormal levels of anxiety and depression, respectively. Structural equation modeling was used to define two composite latent bleeding harm and emotional harm factors. Emotional and bleeding harms were associated with younger age, a belief that one's health is due to luck, having multiple comorbidities, having a history of prior VTE events, having multiple barriers to VTE care, and experiencing medical mistakes in diagnosis or treatment. Emotional harms were uniquely predicted by having poorer health literacy, having low self-reported medication adherence, belief others are responsible for one's health, and more recent VTE events. Bleeding harms were uniquely predicted by having a lower frequency of primary care provider contact and having a history of switching between warfarin and direct oral anticoagulants for VTE treatment. CONCLUSIONS: The findings show high levels of self-reported bleeding and emotional harms in a general population of VTE sufferers that are clearly associated with readily identifiable demographic, health status, and psychosocial characteristics. These represent targets for intervention and changes in clinical practice.

Genetic Risk Factors for Radiation Vasculopathy.

Purpose: The purpose of this study was to perform a genome-wide scan for polymorphisms associated with risk of vision loss from radiation complications in patients treated with proton beam irradiation for choroidal melanoma. Methods: We identified a cohort of 126 patients at high risk of radiation complications due to tumor location within 2 disc diameters of the optic nerve and/or fovea who provided a blood sample to the Massachusetts Eye and Ear Uveal Melanoma Repository. Controls (n = 76) were defined as patients with visual acuity 20/40 or better 3 years after treatment. Cases (n = 50) were selected as patients with visual acuity 20/200 or worse due to radiation damage 3 years after treatment. Genotyping of these samples was performed using the Omni 2.5 chip (Illumina, Inc.). Results: Hypertension (odds ratio [OR] = 3.749, P = 0.0009), visual acuity at diagnosis of choroidal melanoma (OR = 1.031, P = 0.002), tumor distance to fovea (OR = 0.341, P = 6.52E-05), tumor distance to optic disc (OR = 0.481, P = 5.41E-05), and height of tumor (OR = 1.704, P = 0.0069) were associated with poor vision (20/200 or worse). Individual single nucleotide polymorphism (SNP) analysis was performed controlling for the risk factors identified using stepwise regression and the first principal component. Although this analysis determined that there were 74,529 nominally significant SNPs (P < 0.05), there were no SNPs that reached genome-wide significance (P < 5E-08). The SNP reaching the highest significance level (P < 1E-04) was rs11678387, located on chromosome 2, intergenic between EPB41L5/RALB (P = 4.43E-05). Conclusions: Visual loss from radiation vasculopathy after treatment for choroidal melanoma is not only related to tumor location but may be influenced by hypertension and possibly genetic factors.

Long-term Outcomes After Proton Beam Irradiation in Patients With Large Choroidal Melanomas.

Importance: Although radiotherapy has been used more frequently in past decades for the management of large melanomas, long-term efficacy of proton beam irradiation (PBI) of large choroidal melanomas has not been reported. Objective: To evaluate long-term outcomes in patients who underwent PBI for the treatment of large choroidal melanomas. Design, Setting, and Participants: Data were obtained at a single Boston, Massachusetts, academic tertiary referral practice for this retrospective cohort study. In total, 336 patients with large tumors treated over a 13-year period from January 1, 1985, to December 31, 1997, and followed up until the end points were reached or until December 31, 2008, were included. Data analyses were initially completed in February 2017 and finalized in July 2017. Large tumors were those with a height 10 mm or greater or a longest linear diameter greater than 16 mm or a height greater than 8 mm when the optic nerve was involved. Intervention: Proton beam irradiation (total 70 Gy) delivered in 5 equal fractions. Main Outcomes and Measures: The primary outcomes of rates of visual acuity retention, eye retention, tumor recurrence, and melanoma-related mortality were calculated using Kaplan-Meier estimates, and Cox proportional hazards regression analyses were completed to evaluate risk factors for tumor recurrence and melanoma-related mortality. Results: In this cohort of 336 patients with large tumors, 150 were women and 329 were white; mean (SD) age was 60.0 (14.0) years. Of 178 patients without optic nerve involvement (tumor >1 disc diameter from optic nerve), the mean (SD) largest basal diameter was 18.1 (1.9) mm and mean height was 8.2 (2.7) mm. Optic nerve involvement and tumors greater than 8 mm were observed in 109 patients (32.4% of the cohort). Baseline visual acuity of 20/200 or better was observed in 244 patients (72.6%), and worse than 20/800 in 52 (15.5%). Ten-year rates of visual acuity retention were 8.7% (95% CI, 4.1%-15.6%) for at least 20/200 and 22.4% (95% CI, 15.4%-30.4%) for at least counting fingers. Ten years after PBI therapy, the eye was retained (70.4%; 95% CI, 61.5%-77.6%) and tumor controlled (87.5%; 95% CI, 76.8%-93.5%) in most patients. The 10-year all-cause mortality rate was 60.7% (95% CI, 55.5%-65.9%). Approximately half of the patients died of metastatic uveal melanoma (10-year rate, 48.5%; 95% CI, 43.0%-54.4%). Conclusions and Relevance: This study demonstrates that eye conservation is possible in most cases, with ambulatory vision retained in a small proportion of patients 10 years after PBI. Tumor recurrence rates were low and mortality rates were comparable to those observed after enucleation.

ER stress-induced aggresome trafficking of HtrA1 protects against proteotoxicity.

High temperature requirement A1 (HtrA1) belongs to an ancient protein family that is linked to various human disorders. The precise role of exon 1-encoded N-terminal domains and how these influence the biological functions of human HtrA1 remain elusive. In this study, we traced the evolutionary origins of these N-terminal domains to a single gene fusion event in the most recent common ancestor of vertebrates. We hypothesized that human HtrA1 is implicated in unfolded protein response. In highly secretory cells of the retinal pigmented epithelia, endoplasmic reticulum (ER) stress upregulated HtrA1. HtrA1 co-localized with vimentin intermediate filaments in highly arborized fashion. Upon ER stress, HtrA1 tracked along intermediate filaments, which collapsed and bundled in an aggresome at the microtubule organizing center. Gene silencing of HtrA1 altered the schedule and amplitude of adaptive signaling and concomitantly resulted in apoptosis. Restoration of wild-type HtrA1, but not its protease inactive mutant, was necessary and sufficient to protect from apoptosis. A variant of HtrA1 that harbored exon 1 substitutions displayed reduced efficacy in rescuing cells from proteotoxicity. Our results illuminate the integration of HtrA1 in the toolkit of mammalian cells against protein misfolding and the implications of defects in HtrA1 in proteostasis.

Genetics of age-related macular degeneration (AMD).

Age-related macular degeneration (AMD) is a progressive blinding disease and represents the leading cause of visual impairment in the aging population. AMD affects central vision which impairs one's ability to drive, read and recognize faces. There is no cure for this disease and current treatment modalities for the exudative form of the disease require repeated intravitreal injections which may be painful, are incompletely efficacious, and represent a significant treatment burden for both the patient and physician. As such, AMD represents a significant and important clinical problem.It is anticipated that in three years' time, 196 million individuals will be affected with AMD. Over 250 billion dollars per year are spent on care for AMD patients in the US. Over half of the heritability is explained by two major loci, thus AMD is considered the most well genetically defined of the complex disorders. A recent GWAS on 43,566 subjects identified novel loci and pathways associated with AMD risk, which has provided an excellent platform for additional functional studies. Genetic variants have been investigated, particularly with respect to anti-VEGF treatment, however to date, no pharmacogenomic associations have been consistently identified across these studies. It may be that if the goal of personalized medicine is to be realized and biomarkers are to have predictive value for determining the magnitude of risk for AMD at the genetic level, one will need to examine the relationships between these pathways across disease state and relative to modifiable risk factors such as hypertension, smoking, body mass index, and hypercholesterolemia. Further studies investigating protective alleles in populations with low AMD prevalence may lead to this goal.

Factors predicting self-reported medication low adherence in a large sample of adults in the US general population: a cross-sectional study.

OBJECTIVES: The study objective was to determine the level and correlates of self-reported medication low adherence in the US general population. SETTING: A 30 min cross-sectional online survey was conducted with a national sample of adults. PARTICIPANTS: 9202 adults (aged 18+) who had filled at least three or more prescriptions at a community pharmacy in the past 12 months. PRIMARY AND SECONDARY OUTCOME MEASURES: Self-reported medication adherence was measured with the 8-item Morisky Medication Adherence Scale. RESULTS: Low adherence was reported by 42.0%, 29.4% had medium adherence and 28.6% had high adherence. Low adherence was significantly associated with: lower age, being of Hispanic origin or African-American, having difficulty with healthcare, medication or transportation costs, needing the support of others to access primary care, health limiting activity, using multiple providers, infrequent visits to primary care providers and visiting an emergency department >3 times in last 12 months. CONCLUSIONS: A very high level of low medication adherence is seen in the general population, particularly for ethnic minorities, those who use multiple healthcare providers and those who experience barriers to access for regular primary care. As clinical, patient education and counselling, and healthcare policy initiatives are directed to tracking the problem of low medication adherence, these should be priority populations for research and interventions.

Retinopathy of prematurity: A comprehensive risk analysis for prevention and prediction of disease.

BACKGROUND: Retinopathy of prematurity (ROP) is a blinding morbidity of preterm infants. Our current screening criteria have remained unchanged since their inception and lack the ability to identify those at greatest risk. OBJECTIVES: We sought to comprehensively analyze numerous proposed maternal, infant, and environmental ROP risk variables in a robustly phenotyped population using logistic regression to determine the most predictive model for ROP development and severity. We further sought to determine the statistical interaction between significant ROP risk variables, which has not previously been done in the field of ROP. We hypothesize that our comprehensive analysis will allow for better identification of risk variables that independently correlate with ROP disease. Going forward, this may allow for improved infant risk stratification along a time continuum from prenatal to postnatal development, making prevention more feasible. METHODS: We performed a retrospective cohort analysis of preterm infants referred for ROP screening in one neonatal intensive care unit from 2010-2015. The primary outcome measure was presence of ROP. Secondary outcome measures were ROP requiring treatment and severe ROP not clearly meeting current treatment criteria. Univariate, stepwise regression and statistical interaction analyses of 57 proposed ROP risk variables was performed to identify variables which were significantly associated with each outcome measure. RESULTS: We identified 457 infants meeting our inclusion criteria. Within this cohort, numerous factors showed a significant individual association with our ROP outcome measures; however, stepwise regression analysis found the most predictive model for overall ROP risk included estimated gestational age, birth weight, the need for any surgery, and maternal magnesium prophylaxis. The corresponding Area Under the Curve (AUC) for this model was 0.8641, while the traditional model of gestational age and birth weight predicted ROP disease less well with an AUC of 0.8489. Development of severe ROP was best predicted by estimated gestational age (week), the need for any surgery and increased probability of death or moderate-severe BPD at 7 days. Finally, the model most predictive for type 1 ROP included estimated gestational age (week) and the presence of severe chronic lung disease. No significant statistical interaction was found between variables. CONCLUSIONS: Our work is unique as we report comprehensive analysis of the greatest number of proposed ROP risk variables to date in a robustly phenotyped population. We describe novel risk models for our ROP outcome measures and demonstrate independence of these variables using statistical modeling not previously applied to ROP. This may better allow for individual infant risk stratification and importantly mitigation of future risk.

Adherence to Glaucoma Medications Over 12 Months in Two US Community Pharmacy Chains.

UNLABELLED: This study determined the degree of adherence to medications for glaucoma among patients refilling prescriptions in community pharmacies. METHODS: Data abstracted from the dispensing records for 3615 adult patients (18 years or older, predominantly over 45) receiving glaucoma medications from two retail pharmacy chains (64 stores in total) were analyzed. From a 24-month historic data capture period, the 12-month levels of adherence were determined using standard metrics, the proportion of days covered (PDC) and the medication possession ratio (MPR). The overall 12-month mean PDC was only 57%, and the mean MPR was 71%. Using a criterion by which 80% coverage was considered satisfactory adherence, only 30% had satisfactory overall 12-month PDC coverage, and only 37% had satisfactory overall 12-month MPR coverage. Refill adherence increased with age and was highest in the 65-and-older age group (p < 0.001). Differential adherence was found across medication classes, with the highest satisfactory coverage seen for those taking alpha2-adrenergic agonists (PDC = 36.0%; MPR = 47.6%) down to those taking direct cholinergic agonists (PDC = 25.0%; MPR = 31.2%) and combination products (PDC = 22.7%; MPR = 31.0%). Adherence to glaucoma medications in the community setting, as measured by pharmacy refill data, is very poor and represents a critical target for intervention. Community pharmacists are well positioned to monitor and reinforce adherence in this population.

Visual Outcomes after Proton Beam Irradiation for Choroidal Melanomas Involving the Fovea.

PURPOSE: To report visual outcomes in patients undergoing proton beam irradiation of tumors located within 1 disc diameter of the fovea. DESIGN: Retrospective review. PARTICIPANTS: Patients with choroidal melanoma involving the fovea treated with proton beam therapy between 1975 and 2009. METHODS: Three hundred fifty-one patients with choroidal melanomas located 1 disc diameter (DD) or less from the fovea and more than 1 DD away from the optic nerve were included in this study. In a subgroup of 203 of the patients with small and medium choroidal melanomas, the effect of a reduced dose of radiation, 50 Gy (relative biological effectiveness [RBE]) versus 70 Gy (RBE), on visual outcomes was analyzed. The Kaplan-Meier method and Cox regression analysis were performed to calculate cumulative rates of vision loss and to assess risk factors for vision loss, respectively. MAIN OUTCOME MEASURES: Visual acuity and radiation complications, which included radiation maculopathy, papillopathy, retinal detachment, and rubeosis, were assessed. RESULTS: Three hundred fifty-one patients were included in this study with a mean follow-up time of 68.7 months. More than one-third of patients (35.5%) retained 20/200 or better vision 5 years after proton beam irradiation. For those patients with a baseline visual acuity of 20/40 or better, 16.2% of patients retained this level of vision 5 years after proton beam irradiation. Tumor height less than 5 mm and baseline visual acuity 20/40 or better were associated significantly with a better visual outcome (P < 0.001). More than two-thirds (70.4%) of patients receiving 50 Gy (RBE) and nearly half (45.1%) of patients receiving 70 Gy (RBE) retained 20/200 or better vision 5 years after treatment, but this difference was not significant. Approximately 20% of patients with these smaller macular tumors retained 20/40 vision or better 5 years after irradiation. CONCLUSIONS: The results of this retrospective analysis demonstrate that despite receiving a full dose of radiation to the fovea, many patients with choroidal melanoma with foveal involvement maintain useful vision. A radiation dose reduction from 70 to 50 Gy (RBE) did not seem to increase the proportion of patients who retain usable vision.

Ancestry of the Timorese: age-related macular degeneration associated genotype and allele sharing among human populations from throughout the world.

We observed that the third leading cause of blindness in the world, age-related macular degeneration (AMD), occurs at a very low documented frequency in a population-based cohort from Timor-Leste. Thus, we determined a complete catalog of the ancestry of the Timorese by analysis of whole exome chip data and haplogroup analysis of SNP genotypes determined by sequencing the Hypervariable I and II regions of the mitochondrial genome and 17 genotyped YSTR markers obtained from 535 individuals. We genotyped 20 previously reported AMD-associated SNPs in the Timorese to examine their allele frequencies compared to and between previously documented AMD cohorts of varying ethnicities. For those without AMD (average age > 55 years), genotype and allele frequencies were similar for most SNPs with a few exceptions. The major risk allele of HTRA1 rs11200638 (10q26) was at a significantly higher frequency in the Timorese, as well as 3 of the 5 protective CFH (1q32) SNPs (rs800292, rs2284664, and rs12066959). Additionally, the most commonly associated AMD-risk SNP, CFH rs1061170 (Y402H), was also seen at a much lower frequency in the Korean and Timorese populations than in the assessed Caucasian populations (C ~7 vs. ~40%, respectively). The difference in allele frequencies between the Timorese population and the other genotyped populations, along with the haplogroup analysis, also highlight the genetic diversity of the Timorese. Specifically, the most common ancestry groupings were Oceanic (Melanesian and Papuan) and Eastern Asian (specifically Han Chinese). The low prevalence of AMD in the Timorese population (2 of 535 randomly selected participants) may be due to the enrichment of protective alleles in this population at the 1q32 locus.

Analysis of Genetic and Environmental Risk Factors and Their Interactions in Korean Patients with Age-Related Macular Degeneration.

PURPOSE: To investigate the association of genetic and environmental factors, and their interactions in Korean patients with exudative age-related macular degeneration (AMD). METHODS: A total of 314 robustly characterized exudative AMD patients, including 111 PCV (polypoidal choroidal vasculopathy) and 154 typical choroidal neovascularization (CNV), and 395 control subjects without any evidence of AMD were enrolled. Full ophthalmologic examinations including fluorescein angiography (FA), indocyanine green angiography (ICG) and optical coherence tomography (OCT) were done, according to which patients were divided into either PCV or typical CNV. Standardized questionnaires were used to collect information regarding underlying systemic diseases, dietary habits, smoking history and body mass index (BMI). A total of 86 SNPs from 31 candidate genes were analyzed. Genotype association and logistic regression analyses were done and stepwise regression models to best predict disease for each AMD subtype were constructed. RESULTS: Age, spherical equivalent, myopia, and ever smoking were associated with exudative AMD. Age, hypertension, hyperlipidemia, spherical equivalent, and myopia were risk factors for typical CNV, while increased education and ever smoking were significantly associated with PCV (p<.05 for all). Four SNPs, ARMS2/HTRA1 rs10490924, rs11200638, and rs2736911, and CFH rs800292, showed association with exudative AMD. Two of these SNPs, ARMS2/HTRA1 rs10490924 and rs11200638, showed significant association with typical CNV and PCV specifically. There were no significant interactions between environmental and genetic factors. The most predictive disease model for exudative AMD included age, spherical equivalent, smoking, CFH rs800292, and ARMS2 rs10490924 while that for typical CNV included age, hyperlipidemia, spherical equivalent, and ARMS2 rs10490924. Smoking, spherical equivalent, and ARMS2 rs10490924 were the most predictive variables for PCV. When comparing PCV cases to CNV cases, age, BMI, and education were the most predictive risk factors of PCV. CONCLUSIONS: Only one locus, the ARMS2/HTRA1 was a significant genetic risk factor for Korean exudative AMD, including its subtypes, PCV and typical CNV. Stepwise regression revealed that CFH was important to risk of exudative AMD in general but not to any specific subtype. While increased education was a unique risk factor to PCV when compared to CNV, this association was independent of refractive error in this homogenous population from South Korea. No significant interactions between environmental and genetic risk factors were observed.

Plasma homocysteine and genetic variants of homocysteine metabolism enzymes in patients from central Greece with primary open-angle glaucoma and pseudoexfoliation glaucoma.

BACKGROUND: The purpose of this study was to investigate plasma homocysteine levels and polymorphisms in genes encoding enzymes in the metabolic pathway of homocysteine in association with primary open-angle glaucoma (POAG) and pseudoexfoliation glaucoma (PXFG). METHODS: A total of 156 glaucoma patients (76 with POAG and 80 with PXFG) and 135 controls matched for age and sex were enrolled in this study. Plasma homocysteine levels were measured using a commercially available enzyme-linked immunosorbent assay kit. DNA was extracted from peripheral blood leukocytes and real-time polymerase chain reaction was performed for genotyping of the samples. Patients were genotyped using predesigned TaqMan(®) single nucleotide polymorphism genotyping assays for two exon variations (rs1801131, rs1801133) in the 5,10-methylenetetrahydrofolate reductase (MTHFR) gene and one intron variation (rs8006686) in the methylenetetrahydrofolate dehydrogenase (MTHFD1) gene. RESULTS: Homocysteine levels were slightly higher in the patient group (POAG and PXFG) compared with controls, but the difference did not reach statistical significance. The minor alleles of the MTHFR single nucleotide polymorphisms showed a protective effect for POAG and showed an increased risk for PXFG, but none of these associations reached statistical significance (P>0.05). The minor allele of MTHFD1 rs8006686 showed a trend for increased risk of both POAG and PXFG (P>0.05). No statistically significant interaction was seen between the genetic variants and homocysteine levels (P>0.05). CONCLUSION: Our results show that neither the examined single nucleotide polymorphisms from genes involved in the pathway of homocysteine metabolism nor the measured homocysteine levels were associated with POAG or PXFG in our study cohort.

Genetic variants associated with severe retinopathy of prematurity in extremely low birth weight infants.

PURPOSE: To determine genetic variants associated with severe retinopathy of prematurity (ROP) in a candidate gene cohort study of US preterm infants. METHODS: Preterm infants in the discovery cohort were enrolled through the Eunice Kennedy Shriver National Institute of Child Health and Human Development Neonatal Research Network, and those in the replication cohort were from the University of Iowa. All infants were phenotyped for ROP severity. Because of differences in the durations of enrollment between cohorts, severe ROP was defined as threshold disease in the discovery cohort and as threshold disease or type 1 ROP in the replication cohort. Whole genome amplified DNA from stored blood spot samples from the Neonatal Research Network biorepository was genotyped using an Illumina GoldenGate platform for candidate gene single nucleotide polymorphisms (SNPs) involving angiogenic, developmental, inflammatory, and oxidative pathways. Three analyses were performed to determine significant epidemiologic variables and SNPs associated with levels of ROP severity. Analyses controlled for multiple comparisons, ancestral eigenvalues, family relatedness, and significant epidemiologic variables. Single nucleotide polymorphisms significantly associated with ROP severity from the discovery cohort were analyzed in the replication cohort and in meta-analysis. RESULTS: Eight hundred seventeen infants in the discovery cohort and 543 in the replication cohort were analyzed. Severe ROP occurred in 126 infants in the discovery and in 14 in the replication cohort. In both cohorts, ventilation days and seizure occurrence were associated with severe ROP. After controlling for significant factors and multiple comparisons, two intronic SNPs in the gene BDNF (rs7934165 and rs2049046, P < 3.1 × 10(-5)) were associated with severe ROP in the discovery cohort and were not associated with severe ROP in the replication cohort. However, when the cohorts were analyzed together in an exploratory meta-analysis, rs7934165 increased in associated significance with severe ROP (P = 2.9 × 10(-7)). CONCLUSIONS: Variants in BDNF encoding brain-derived neurotrophic factor were associated with severe ROP in a large candidate gene study of infants with threshold ROP.

Rare and common variants in extracellular matrix gene Fibrillin 2 (FBN2) are associated with macular degeneration.

Neurodegenerative diseases affecting the macula constitute a major cause of incurable vision loss and exhibit considerable clinical and genetic heterogeneity, from early-onset monogenic disease to multifactorial late-onset age-related macular degeneration (AMD). As part of our continued efforts to define genetic causes of macular degeneration, we performed whole exome sequencing in four individuals of a two-generation family with autosomal dominant maculopathy and identified a rare variant p.Glu1144Lys in Fibrillin 2 (FBN2), a glycoprotein of the elastin-rich extracellular matrix (ECM). Sanger sequencing validated the segregation of this variant in the complete pedigree, including two additional affected and one unaffected individual. Sequencing of 192 maculopathy patients revealed additional rare variants, predicted to disrupt FBN2 function. We then undertook additional studies to explore the relationship of FBN2 to macular disease. We show that FBN2 localizes to Bruch's membrane and its expression appears to be reduced in aging and AMD eyes, prompting us to examine its relationship with AMD. We detect suggestive association of a common FBN2 non-synonymous variant, rs154001 (p.Val965Ile) with AMD in 10 337 cases and 11 174 controls (OR = 1.10; P-value = 3.79 × 10(-5)). Thus, it appears that rare and common variants in a single gene--FBN2--can contribute to Mendelian and complex forms of macular degeneration. Our studies provide genetic evidence for a key role of elastin microfibers and Bruch's membrane in maintaining blood-retina homeostasis and establish the importance of studying orphan diseases for understanding more common clinical phenotypes.

FLT1 genetic variation predisposes to neovascular AMD in ethnically diverse populations and alters systemic FLT1 expression.

PURPOSE: Current understanding of the genetic risk factors for age-related macular degeneration (AMD) is not sufficiently predictive of the clinical course. The VEGF pathway is a key therapeutic target for treatment of neovascular AMD; however, risk attributable to genetic variation within pathway genes is unclear. We sought to identify single nucleotide polymorphisms (SNPs) associated with AMD within the VEGF pathway. METHODS: Using a tagSNP, direct sequencing and meta-analysis approach within four ethnically diverse cohorts, we identified genetic risk present in FLT1, though not within other VEGF pathway genes KDR, VEGFA, or VASH1. We used ChIP and ELISA in functional analysis. RESULTS: The FLT1 SNPs rs9943922, rs9508034, rs2281827, rs7324510, and rs9513115 were significantly associated with increased risk of neovascular AMD. Each association was more significant after meta-analysis than in any one of the four cohorts. All associations were novel, within noncoding regions of FLT1 that do not tag for coding variants in linkage disequilibrium. Analysis of soluble FLT1 demonstrated higher expression in unaffected individuals homozygous for the FLT1 risk alleles rs9943922 (P = 0.0086) and rs7324510 (P = 0.0057). In silico analysis suggests that these variants change predicted splice sites and RNA secondary structure, and have been identified in other neovascular pathologies. These data were supported further by murine chromatin immunoprecipitation demonstrating that FLT1 is a target of Nr2e3, a nuclear receptor gene implicated in regulating an AMD pathway. CONCLUSIONS: Although exact variant functions are not known, these data demonstrate relevancy across ethnically diverse genetic backgrounds within our study and, therefore, hold potential for global efficacy.

Systems biology-based analysis implicates a novel role for vitamin D metabolism in the pathogenesis of age-related macular degeneration.

Vitamin D has been shown to have anti-angiogenic properties and to play a protective role in several types of cancer, including breast, prostate and cutaneous melanoma. Similarly, vitamin D levels have been shown to be protective for risk of a number of conditions, including cardiovascular disease and chronic kidney disease, as well as numerous autoimmune disorders such as multiple sclerosis, inflammatory bowel diseases and type 1 diabetes mellitus. A study performed by Parekh et al. was the first to suggest a role for vitamin D in age-related macular degeneration (AMD) and showed a correlation between reduced serum vitamin D levels and risk for early AMD. Based on this study and the protective role of vitamin D in diseases with similar pathophysiology to AMD, we examined the role of vitamin D in a family-based cohort of 481 sibling pairs. Using extremely phenotypically discordant sibling pairs, initially we evaluated the association of neovascular AMD and vitamin D/sunlight-related epidemiological factors. After controlling for established AMD risk factors, including polymorphisms of the genes encoding complement factor H (CFH) and age-related maculopathy susceptibility 2/HtrA serine peptidase (ARMS2/HTRA1), and smoking history, we found that ultraviolet irradiance was protective for the development of neovascular AMD (p = 0.001). Although evaluation of serum vitamin D levels (25-hydroxyvitamin D [25(OH)D]) was higher in unaffected individuals than in their affected siblings, this finding did not reach statistical significance. Based on the relationship between ultraviolet irradiance and vitamin D production, we employed a candidate gene approach for evaluating common variation in key vitamin D pathway genes (the genes encoding the vitamin D receptor [VDR]; cytochrome P450, family 27, subfamily B, polypeptide 1 [CYP27B1]; cytochrome P450, family 24, subfamily A, polypeptide 1 [CYP24A1]; and CYP27A1) in this same family-based cohort. Initial findings were then validated and replicated in the extended family cohort, an unrelated case-control cohort from central Greece and a prospective nested case-control population from the Nurse's Health Study and Health Professionals Follow-Up Studies, which included patients with all subtypes of AMD for a total of 2,528 individuals. Single point variants in CYP24A1 (the gene encoding the catabolising enzyme of the vitamin D pathway) were demonstrated to influence AMD risk after controlling for smoking history, sex and age in all populations, both separately and, more importantly, in a meta-analysis. This is the first report demonstrating a genetic association between vitamin D metabolism and AMD risk. These findings were also supplemented with expression data from human donor eyes and human retinal cell lines. These data not only extend previous biological studies in the AMD field, but further emphasise common antecedents between several disorders with an inflammatory/immunogenic component such as cardiovascular disease, cancer and AMD.

Influence of ROBO1 and RORA on risk of age-related macular degeneration reveals genetically distinct phenotypes in disease pathophysiology.

ROBO1 is a strong candidate gene for age-related macular degeneration (AMD) based upon its location under a linkage peak on chromosome 3p12, its expression pattern, and its purported function in a pathway that includes RORA, a gene previously associated with risk for neovascular AMD. Previously, we observed that expression of ROBO1 and RORA is down-regulated among wet AMD cases, as compared to their unaffected siblings. Thus, we hypothesized that contribution of association signals in ROBO1, and interaction between these two genes may be important for both wet and dry AMD. We evaluated association of 19 single nucleotide polymorphisms (SNPs) in ROBO1 with wet and dry stages of AMD in a sibling cohort and a Greek case-control cohort containing 491 wet AMD cases, 174 dry AMD cases and 411 controls. Association signals and interaction results were replicated in an independent prospective cohort (1070 controls, 164 wet AMD cases, 293 dry AMD cases). The most significantly associated ROBO1 SNPs were rs1387665 under an additive model (meta P = 0.028) for wet AMD and rs9309833 under a recessive model (meta P = 6 × 10(-4)) for dry AMD. Further analyses revealed interaction between ROBO1 rs9309833 and RORA rs8034864 for both wet and dry AMD (interaction P<0.05). These studies were further supported by whole transcriptome expression profile studies from 66 human donor eyes and chromatin immunoprecipitation assays from mouse retinas. These findings suggest that distinct ROBO1 variants may influence the risk of wet and dry AMD, and the effects of ROBO1 on AMD risk may be modulated by RORA variants.